Table 9: Evaluation results for distinguishing between Grade 1 and Grade 2 to each feature set.

Object

Feature set

TN

FP

FN

TP

SN (%)

SP (%)

PPV (%)

NPV (%)

ACC (%)

NEN

CNF

CLF

Lumen

PLF

ALF

CEF

EN

PEF

AEF

CDF

Duct

PDF

ADF

CTF

Tissue

PTF

ATF

TP (true positive): the number of Grade 2s that are correctly classified as Grade 2s.FP (false positive): the number of Grade 1s that are incorrectly classified as Grade 2s.FN (false negative): the number of Grade 2s that are incorrectly classified as Grade 1s.TN (true negative): the number of Grade 1s that are correctly classified as Grade 1s.